PCL-818 Series 12-bit ISA Multifunction Card User Manual
Copyright The documentation and the software included with this product are copyrighted 2007 by Advantech Co., Ltd. All rights are reserved. Advantech Co., Ltd. reserves the right to make improvements in the products described in this manual at any time without notice. No part of this manual may be reproduced, copied, translated or transmitted in any form or by any means without the prior written permission of Advantech Co., Ltd. Information provided in this manual is intended to be accurate and reliable.
Product Warranty (2 years) Advantech warrants to you, the original purchaser, that each of its products will be free from defects in materials and workmanship for two years from the date of purchase. This warranty does not apply to any products which have been repaired or altered by persons other than repair personnel authorized by Advantech, or which have been subject to misuse, abuse, accident or improper installation.
Declaration of Conformity CE This product has passed the CE test for environmental specifications when shielded cables are used for external wiring. We recommend the use of shielded cables. This kind of cable is available from Advantech. Please contact your local supplier for ordering information. Technical Support and Assistance Step 1. Visit the Advantech web site at www.advantech.com/support where you can find the latest information about the product. Step 2.
Safety Instructions 1. Read these safety instructions carefully. 2. Keep this User's Manual for later reference. 3. Disconnect this equipment from any AC outlet before cleaning. Use a damp cloth. Do not use liquid or spray detergents for cleaning. 4. For plug-in equipment, the power outlet socket must be located near the equipment and must be easily accessible. 5. Keep this equipment away from humidity. 6. Put this equipment on a reliable surface during installation.
20° C (-4° F) OR ABOVE 60° C (140° F). THIS COULD DAMAGE THE EQUIPMENT. THE EQUIPMENT SHOULD BE IN A CONTROLLED ENVIRONMENT. 16. CAUTION: DANGER OF EXPLOSION IF BATTERY IS INCORRECTLY REPLACED. REPLACE ONLY WITH THE SAME OR EQUIVALENT TYPE RECOMMENDED BY THE MANUFACTURER, DISCARD USED BATTERIES ACCORDING TO THE MANUFACTURER'S INSTRUCTIONS. The sound pressure level at the operator's position according to IEC 7041:1982 is no more than 70 dB (A).
Contents Chapter Chapter Chapter 1 Overview .......................................................... 2 1.1 1.2 1.3 1.4 Introduction ....................................................................... 2 Features ............................................................................. 3 Applications ...................................................................... 4 Installation Guide .............................................................. 5 1.5 1.6 1.7 Software Overview..........
C.4 C.5 C.6 C.7 C.8 C.9 C.10 C.11 C.12 C.13 C.14 C.15 C.16 C.17 C.18 C.19 Software A/D Trigger — BASE+00H ........................... 48 A/D RangeControl — BASE+01H ................................ 48 MUX Scan Channel Control — BASE+02H.................. 50 MUX Scan Channel Status — BASE+02H .................... 52 Digital I/O Registers - BASE + 03/0BH ......................... 52 D/A Output — BASE+04/05H ....................................... 53 FIFO Interrupt Control — BASE+06H..........................
CHAPTER 1 2 Overview Sections include: • Introduction • Features • Applications • Installation guide • Software Overview • Device Driver Roadmap • Accessories
Chapter 1 Overview 1.1 Introduction Thank you for buying the Advantech PCL-818HD/HG/L. The PCL818HD/HG/L is a high-performance multifunction data acquisition card for IBM PC/XT/AT or compatible computers. It offers the five most desired measurement and control functions: 12-bit A/D conversion, D/A conversion, digital input, digital output and timer/counter. A programmable-gain instrument amplifier (x 0.5, 1, 2, 4 and 8) lets you acquire different input signals without external signal conditioning.
1.2 Features • 16 single-ended or eight differential analog inputs, switch selectable • 12-bit A/D, up to 100 KHz sampling rate with DMA transfer and different gain for each channel • Software-selectable gain: x 0.5, 1, 2, 4 or 8 • Onboard 1 K word FIFO buffer with software selectable interrupt • Software selectable analog input ranges (VDC): • Bipolar: +/-0.625, +/-1.25, +/-2.5, +/-5, +/-10 • Unipolar: 0 to 1.25, 0 to 2.
Keeping Output Values after System Reset When the system is hot reset (power not shut down), the PCL-818HD/ HG/L can either retain the last analog output values, or return to its default configuration, depending on the jumper setting. This practical function eliminates danger caused by improper operation during unexpected system reset. Board ID The PCL-818HD/HG/L has a built-in DIP Switch that helps define each card’s ID when multiple PCL-818HD/HG/L cards have been installed on the same PC chassis.
1.
Figure 1.
1.5 Software Overview Advantech offers a rich set of DLL drivers, third-party driver support and application software to help fully exploit the functions of your PCL818HD/HG/L card: • Device Drivers (on the companion CD-ROM) • LabVIEW driver • Advantech ActiveDAQ • Advantech GeniDAQ Programming choices for DA&C cards: You may use Advantech application software such as Advantech Device Drivers.
1.6 Device Driver Roadmap This section will provide you a roadmap to demonstrate how to build an application from scratch using Advantech Device Drivers with your favorite development tools such as Visual C++, Visual Basic, Delphi and C++ Builder. The step-by-step instructions on how to build your own applications using each development tool will be given in the Device Drivers Manual. Moreover, a rich set of example source code is also given for your reference.
Programming with Device Drivers Function Library Advantech Device Drivers offer a rich function library that can be utilized in various application programs. This function library consists of numerous APIs that support many development tools, such as Visual C++, Visual Basic, Delphi and C++ Builder.
1.7 Accessories Advantech offers a complete set of accessory products to support the PCL-818HD/HG/L card. These accessories include: Wiring Cables • PCL-10120 The PCL-10120 cable is a 20-pin flat cable for PCL818HD/HG/L cards. • PCL-10137 The PCL-10137 shielded cable is specially designed for PCL-818HD/HG/L cards to provide high resistance to noise.
CHAPTER 2 2 Installation Sections include: • Unpacking • Driver Installation • Hardware Installation • Device Setup & Configuration
Chapter 2 Installation 2.1 Unpacking After receiving your PCL-818HD/HG/L package, please inspect its contents first. The package should contain the following items: • PCL-818HD/HG/L card • Companion CD-ROM (Device Drivers included) • User’s Manual The PCL-818HD/HG/L card harbors certain electronic components vulnerable to electrostatic discharge (ESD). ESD can easily damage the integrated circuits and certain components if preventive measures are ignored.
2.2 Driver Installation We recommend you to install the driver before you install the PCL818HD/HG/L card into your system, since this will guarantee a smooth installation process. The Advantech Device Drivers Setup program for the PCL-818HD/HG/L card is included in the companion CD-ROM that is shipped with your DA&C card package. Please follow the steps below to install the driver software: Step 1: Insert the companion CD-ROM into your CD-ROM drive.
Step 3: Select the Device Drivers option. Step 4: Select the specific device then just follow the installation instructions step by step to complete your device driver installation and setup. Figure 2.
2.3 Hardware Installation Note: Make sure you have installed the driver first before you install the card (please refer to 2.2 Driver Installation) After the Device Drivers installation is completed, you can then install the PCL-818HD/HG/L card into any PCI slot on your computer. However, it is suggested that you refer to the computer user’s manual or related documentation if you have any doubt. Please follow the steps below to install the card onto your system.
2.4 Device Setup & Configuration The Advantech Device Manager program is a utility that allows you to set up, configure and test your device, and later stores your settings on the system registry. These settings will be used when you call the APIs of Advantech Device Drivers. Setting Up the Device Step 1:To install the I/O device for your card, you must first run the Device Installation program (by accessing Start/Advantech Automation/Device Manager/Advantech Device Manager ).
Step 3:Scroll down the List of Devices box to find the device that you wish to install, then click the Add… button. You will see a Device Setting dialog box such as the one in Fig. 2-4. Configuring the Device Step 4:On the Device Setting dialog box (Fig. 2-4), you can configure the A/D channels configuration either as 8 Differential or 16 Singleended, and specify the D/A voltage reference either as External or Internal. Figure 2.
Figure 2.5: Device Name After your card is properly installed and configured, you can click the Test… button to test your hardware by using the testing utility supplied.
Figure 2.6: Test Utility For more detailed information, please refer to Chapter 2 of the Device Drivers Manual. You can also find the rich examples on the CD-ROM to speed up your programming.
PCL-818 Series User Manual 20
CHAPTER 3 2 Signal Connections Sections include: • Overview • Switch & Jumper Settings • Signal Connections • Field Wiring Considerations
Chapter 3 Signal Connections 3.1 Overview Maintaining signal connections is one of the most important factors in ensuring that your application system is sending and receiving data correctly. A good signal connection can avoid unnecessary and costly damage to your PC and other hardware devices. This chapter provides useful information about how to connect input and output signals to the PCL818HD/HG/L via the I/O connector. 3.
Base Address Selection (SW1) You control the PCL-818HD/HG/L's operation by reading or writing data to the PC's I/O (input/output) port addresses. The PCL-818HD/HG/L requires 32 consecutive address locations with the FIFO buffer enabled or 16 locations with the FIFO disabled. Switch SW1 sets the card's base (beginning) address. Valid base addresses range from Hex 000 to Hex 3F0. Other devices in your system may, however, be using some of these addresses.
Channel Configuration, S/E or DIFF (SW2) The PCL-818HD/HG/L offers 16 single-ended or eight differential analog input channels. Slide switch SW2 changes the channels between single-ended or differential input. Slide the switch to the left-hand position, marked DIFF, for eight differential inputs (the default) or to the righthand position, marked S/E, for 16 single-ended inputs.
Table 3-3: Jumper JP11 Settings Jumpers Function Description JP11 External Internal (default) When you set JPI1 to INT, the D/A converter takes its reference voltage input from the card's on-board reference. Jumper JP10 selects either -5 V or -10 V on-board reference voltage. With JP11 set to INT the D/A channel has an output range of 0 to +5 V or 0 to +10 V, respectively. When you set JP11 to EXT, the D/A converter takes its reference voltage input from pin 31 of connector CN3.
Internal Voltage Reference, -10 V or -5 V (JP10) If you use an internal reference voltage (set with JP11), the PCL-818HD/ HG/L provides a choice of DC internal reference voltage sources: -5 V and -10 V. Table 3-4: Jumper JP10 Settings Jumpers Function Description JP10 5 V (default) 10 V Timer Clock Selection (JP8) The PCL-818HD/HG/L’s JP8 controls the input clock frequency for the 8254 programmable clock/timer. You have two choices: 10 MHz and 1 MHz.
FIFO Enable/Disable (JP6) When you enable the PCL-818HD/HG 's FIFO (First In First Out) buffer, each time the card makes an A/D reading, it will store the data in both the A/D output registers (accessed at addresses BASE+0/1) and in the FIFO buffer (accessed at BASE+23/24). When you enable the FIFO, the PCL818HD/HG will require 32 consecutive I/O addresses. When you disable the FIFO buffer, you can only access the converted data from the A/D output registers at BASE+O/1.
We recommend that you leave JP5 set to the default DIO and DI2, because the software driver requires this setting. FIFO Interrupt Selection (JP9) The PCL-818HD/HG’s JP9 controls the interrupt (2 through 7) that the FIFO generates when it is half full. The FIFO interrupt control register, BASE+6, enables and disables this interrupt.
Table 3-8: Jumper Settings Jumpers Function Description JP1 (first) S0 D0 (default) JP1 (second) S1 D1 (default) JP1 (third) S2 D2 (default) JP1 (fourth) S3 D3 (default) 29 Chapter 3
3.3 Signal Connections 3.3.1 Pin Assignments Figure 3-2 shows the pin assignments for the 37-pin I/O connector. D/O 0 D/O 2 D/O 4 D/O 6 D/O 8 D/O 10 D/O 12 D/O 14 D.GND +5 V CN1 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 D/O 1 D/O 3 D/O 5 D/O 7 D/O 9 D/O 11 D/O 13 D/O 15 D.GND +12 V D/I 0 D/I 2 D/I 4 D/I 6 D/I 8 D/I 10 D/I 12 D/I 14 D.GND +5 V CN3 (Single ended) CN2 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 D/I 1 D/I 3 D/I 5 D/I 7 D/I 9 D/I 11 D/I 13 D/I 15 D.
3.3.2 I/O Connector Signal Description Table 3-9 I/O Connector Signal Descriptions Signal Name Reference Direction Description A/D S <0..15> A.GND Input Analog input (single-ended), channels 0 through 15. A/D H <0..7> A.GND Input Analog input high (differential), channels 0 through 7. A/D L <0..7> A.GND Input Analog input low (differential), channels 0 through 7. D/A A.GND Output Analog output AGND Analog Ground. The two ground references (A.GND and D.GND) are connected together on the PCL-818HD/HG/L card.
Differential Channel Connections Differential input connections use two signal wires per channel. The card measures only the voltage difference between these two wires, the HI wire and the LOW wire. If the signal source has no connection to ground, it is called a "floating" source. A connection must exist between LOW and ground to define a common reference point for floating signal sources. To measure a floating sources connect the input channels as shown below: HIGH + + Vs - LO W + Vin - A.
Correct Connection HIGH + + Vs - LOW + Vin - Vin=Vs - - + Vcm GND Incorrect Connection HIGH + + Vs - + Vin - Vin=Vs+Vcm LOW - + - Vcm GND Expanding Analog Inputs You can expand any or all of the PCL-818HD/HG/L's A/D input channels using multiplexing daughterboards. Daughterboards without D-type connectors require the PCLD-774 Analog Expansion Board. The PCLD-789(D) Amplifier and Multiplexer multiplexes 16 differential inputs to one A/D input channel.
The PCLD-8115 Screw Terminal Board makes wiring connections easy. It provides 20-pin flat cable and DB-37 cable connectors. It also includes CJC (Cold Junction Compensation) circuits. Special circuit pads on the PCLD-8115 accommodate passive signal conditioning components. You can easily implement a low-pass filter, attenuator or current shunt by adding resistors and capacitors. Analog Output Connection The PCL-818HD/HG/L provides one D/A output channel.
Digital Signal Connections The PCL-818HD/HG/L has 16 digital input and 16 digital output channels. The digital I/O levels are TTL compatible. The following figure shows connections to exchange digital signals with other TTL devices: TTL Devices DO DI D.GND D.GND To receive an OPEN/SHORT signal from a switch or relay, add a pull-up resistor to ensure that the input is held at a high level when the contacts are open. See the figure below: +5V 4.7K D.
3.4 Field Wiring Considerations When you use the PCL-818HD/HG/L to acquire data from outside, noises in the environment might significantly affect the accuracy of your measurements if due cautions are not taken. The following measures will be helpful to reduce possible interference running signal wires between signal sources and the PCL-818HD/HG/L.
APPENDIX A 2 Specifications
Appendix A Specifications A.1 Analog Input Channels 16 single-ended or 8 differential or combination Resolution 12-bit FIFO Size 4K samples (for PCL-818HD/HG only) PCL-818HD Max. Sam- 100 KS/s pling Rate1 PCL-818HG Max. Sam- Gain 0.5, 1 5, 10 50, 100 500, 1000 pling Rate Speed 100 KS/s 35 KS/s 7 KS/s 770 S/s PCL-818L Max. Sam- 40 KS/s pling Rate1 Conversion Time 8 µs Input range and Gain 0.5 1 2 4 8 Gain List for PCLUnipolar N/A 0~10 0~5 0~2.5 0~1.25 818HD Bipolar ±10 ±5 ±2.5 ±1.25 ±0.
A.2 Analog Output Channels Resolution Output Range (Internal & External Reference) 1 12-bit Using Internal Reference 0 ~ +5V, 0 ~ +10 V Using External Reference -10V ~ +10 V Accuracy Relative Differential Non-linearity Adjustable to zero 10V/s 40 ppm/ 3 mA 100 K samples/s 0.81 (min.) 5 MHz 26s (to ±1/2 LSB of FSR) Internal External ±0.5 LSB ±0.5 LSB (monotonic) Gain Error Slew Rate Drift Driving Capability Max.
A.4 Counter/Timer Device Channels Compatibility Base Clock Pacer output Intel 8254 or equivalent 3 channels, 16 bits. 2 channels are permanently configured as programmable pacers; 1 channel is free for your application TTL/CMOS Channel 2: Takes input from output of channel 1 Channel 1: 10 MHz or 1MHz, switch selectable Channel 0: Internal 100 KHz or external clock (10 MHz max.), selected by software 0.00023 Hz (71 minutes/pulse) to 2.5 MHz A.
APPENDIX B 2 Block Diagram
Appendix B Block Diagram B.
C APPENDIX 2 Register Structure & Format
Appendix C Register Structure & Format C.1 Overview The PCL-818HD/HG/L is delivered with an easy-to-use 32-bit Device Drivers for user programming under the Windows 95/98/NT/2000/ME/ XP operating system. We advise users to program the PCL-818HD/HG/L using the 32-bit Device Drivers provided by Advantech to avoid the complexity of low-level registry programming. The most important consideration in programming the PCL-818HD/HG/ L the register level is to understand the function of the card's registers.
Table C-1 PCL-818HD/HG/L Register Format (Part 1) Base Addr.
Table C-1 PCL-818HD/HG/L Register Format (Part 2) Base Addr.
Table C-1 PCL-818HD/HG/L Register Format (Part 3) Base Addr. +HEX 14H R 17H 19H 6 5 4 3 2 1 0 N/A W Clear FIFO Interrupt Request R A/D data and channels from FIFO AD3 AD2 AD1 AD0 C3 N/A C2 C1 C0 AD6 AD5 AD4 W A/D data and channels from FIFO AD11 AD10 AD9 AD8 AD7 N/A R FIFO status W FIFO clear FF HF EF W 18H 7 R C.
C.4 Software A/D Trigger — BASE+00H You can trigger an A/D conversion from software, the card's on-board pacer or an external pulse. If you select software triggering, a write to the register BASE+00H with any value will trigger an A/D conversion. Bits 1 and 0 of register BASE+09H select the trigger source. See pages 57 and 58 for BASE+09H register layout and programming information.
Range codes appear below: PCL-818HD Input Range (V) -5 to +5 -2.5 to +2.5 -1.25 to +1.25 -0.625 to +0.625 0 to 10V 0 to 5V 0 to 2.5V 0 to 1.25V -10V to +10V N/A N/A N/A N/A N/A N/A N/A PCL-818HG Input Range (V) ±5V ±0.5V ±0.05V ±0.005V 0 to 10V 0 to 1V 0 to 0.1V 0 to 0.01V ±10V ±1V ±0.1V ±0.
PCL-818L Input Range JP7=5V ±5V ±2.5V ±1.25V ±0.625V Note: Range Code G1 0 0 1 1 JP7=10V ±10V ±5V ±2.5V ±1.25V G0 0 1 0 1 G3 and G2 are not used for PCL-818L. C.6 MUX Scan Channel Control — BASE+02H The write register at BASE+02H controls multiplexer (MUX) scanning. The high nibble provides the stop scan channel number, and the low nibble provides the start scan channel number. Writing to this register automatically initializes the MUX to the start channel.
Table C-5 Register for MUX Scan Channel Control Write MUX scan channel control Bit # 7 6 5 4 3 2 1 0 BASE + 02H CH3 CH2 CH1 CH0 CL3 CL2 CL1 CL0 CH3 ~ CH0 Stop scan channel number CH0 the least significant bit (LSB) of the stop channel CH3 the most significant bit (MSB) CL3 ~ CL0 Start scan channel number CL0 the least significant bit (LSB) of the start channel CL3 the most significant bit (MSB) The MUX scan register low nibble, CL3 to CL0, also acts as a pointer when you program
C.7 MUX Scan Channel Status — BASE+02H Read register BASE+02H to get the current multiplexer (MUX) channel. Table C-6 Register for MUX Scan Channel Status Read MUX scan channel status Bit # 7 6 5 4 BASE + 02H 3 2 1 0 CC3 CC2 CC1 CC0 CC3 ~ CC0 Current channel number CC0 the least significant bit (LSB) of the stop channel CC3 the most significant bit (MSB) C.8 Digital I/O Registers - BASE + 03/0BH The PCL-818HD/HG/L provides 16 digital input channels and 16 digital output channels.
Table C-8 Register for Digital Output Read Digital Input Bit # 7 6 5 4 3 2 1 0 BASE + 03H DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 BASE + 0BH DI15 DI14 DI13 DI12 DI11 DI10 DI9 DI8 DI15 ~ DI0 Digital input data DI0 the least significant bit (LSB) of the DI data DI15 the most significant bit (MSB) Note: Digital Outputs D0 - D3 is selectable from the 20pin connector or the 37-pin D connector. Please refer to chapter 2 for details. C.
When you write data to the D/A channels, write the low byte first. The low byte is temporarily held by a register in the D/A and not released to the output. After you write the high byte, the low byte and high byte are added and passed to the D/A converter. This double buffering process protects the D/A data integrity through a single step update. The PCL-818HD/HD/L provides a precision fixed internal -5 V or -10 V reference, selectable by means of Jumper JP10.
C.11 Clear Interrupt Request — BASE+08H Write any value to register BASE+08H to clear the interrupt request. Table C-11 Register for Clear Interrupt Request Write A/D control Bit # 7 6 5 4 3 2 1 0 BASE + 09H X X X X X X X X C.12 A/D Status — BASE+08H Read-only register BASE+08H provides information on the A/D configuration and operation.
Note: This bit is used for PCL-818L. MUX Single-ended/differential channel indicator 0 8 differential channels 1 16 single-ended channels INT Data valid 0 No A/D conversion has been completed since the last time the INT bit was cleared. Values in the A/D data registers are not valid data. 1 The A/D conversion has finished, and converted data is ready.
C.13 A/D Control — BASE+09H Read/write register BASE+09H provides information on the PCL818HD/HG/L's operating modes. Table C-13 Register for A/D Control Read/Write A/D control Bit # 7 6 5 4 BASE + 09H INTE I2 I1 I0 3 2 1 0 DMAE ST1 ST0 INTE Disable/enable generated interrupts 0 Disables the generation of interrupts. No interrupt signal can be sent to the PC bus. Enables the generation of interrupts.
Note: Make sure that the IRQ level you choose is not being used by another I/O device. DMAE Disable/enable DMA transfers 0 Disables DMA transfers 1 Enables DMA transfer. Each A/D conversion initiates two successive DMA request signals. These signals cause the 8237 DMA controller to transfer two bytes of conversion data from the PCL-818HD/HG/L to memory. Note: You must program the PC's 8237 DMA controller the DMA page register before you set DMAE to 1.
C.14 Timer/Counter Enable — BASE+0AH Write register BASE+0AH enables or disables the PCL-818HD/HG/L's timer/counter. Table C-14 Register for Timer/Counter Enable Write Timer/Counter enable Bit # 7 6 5 4 3 2 BASE + 0AH 1 0 TC1 TC0 TC0 Disable/enable pacer 0 Pacer enabled 1 Pacer controlled by TRIG0. This blocks trigger pulses sent from the pacer to the A/D until TRIG0 is taken high.
C.16 Clear FIFO Interrupt Request — BASE+14H Write any value to this I/O port to clear the FIFO's interrupt request. Table C-15 Register for Clear FIFO Interrupt Request Write Clear FIFO Interrupt Request Bit # 7 6 5 4 3 2 1 0 BASE + 14H X X X X X X X X Note: This register is not used for PCL-818L. C.17 A/D Data and Channel from FIFO - BASE + 17/18H The PCL-818HD/HG stores data from A/D conversions in a 1 K word First-In First-Out (FIFO) data buffer.
C.18 FIFO Status — BASE+19H The register at BASE+19H clears the FIFO buffer and sets its empty flag (EF). The FIFO status register, address BASE+19H, has flags which you can read to determine the current state of the FIFO buffer, including full flag, half-full flag, and empty flag.
C.19 FIFO Clear — BASE+19H Writing any value to BASE+19H clears all data in the FIFO and sets the empty flag (EF) to 1. Table C-18 Register for FIFO Clear Write Bit # BASE + 19H Note: FIFO clear 7 6 X X 5 X 4 X 3 X 2 X This register is not used for PCL-818L.
APPENDIX D 2 Calibration
Appendix D Calibration This chapter provides brief information on PCL-818HD/HG/L calibration. Regular calibration checks are important to maintain accuracy in data acquisition and control applications. We provide the calibration program on the companion CD-ROM to assist you in D/A calibration. Note: If you installed the program to another directory, you can find these programs in the corresponding subfolders in your destination directory. The PCL-818HD/HG/L is calibrated at the factory for initial use.
D.1 VR Assignment The six variable resistors (VRs) on the PCL-818HD/HG/L board help you make accurate adjustment on all A/D and D/A channels. See the figure in Appendix B for help finding the VRs. The following list shows the function of each VR: VR Function VR1 A/D unipolar offset VR2 A/D full scale VR3 A/D bipolar offset VR4 PGA offset VR5 D/A full scale VR6 D/A offset Figure D.
D.2 A/D Calibration Note: Using a precision voltmeter to calibrate the A/D outputs is recommended. Regular and accurate calibration ensures maximum possible accuracy. The CALB.EXE calibration program leads you through the whole A/D offset and gain adjustment procedure. The basic steps are outlined below: 1. Short the A/D input channel 0 to ground and measure the voltage at TP1 on the PCB (see the figure in Appendix B). Adjust VR4 until TP1 is as close as possible to 0 V. 2.
