User guide

12
Before connecting any power or inputs to the unit, ensure that all signal wires and
power cables are at zero voltage. The DC power is applied to the unit via a three-way
screw terminal connector. The power supply is supplied with two tinned leads; the
positive lead is identified by the RED shroud over the wire. The third connection is for
system GROUND. You will require a small flat-head screwdriver. Connect the power
and signal wires accordingly, noting carefully all polarities. Ensure that the unit is
properly grounded to a suitable ground within the cabinet.
Loosen the screws on the terminal block and insert the exposed conductor cable from
the power supply below the screws, under the metal plate. Ensure that the insulation is
flush with the terminal block. If it is too long, remove the cable, trim and reinsert.
Tighten the screw to firmly hold the cable. Ensure the ground wire is connected and
properly grounded at the other end. If you are not using the supplied wall power supply,
follow the same procedure carefully identifying the positive supply line. The unit is
protected against reverse polarity but not against substantial over voltage.
2.3.2 Input Signal Connections
The maximum input on any input channel is 25 Volts DC. Voltages
higher than this may permanently damage the unit.
Ensure the unit is powered down before connecting any inputs.
There are two universal analog inputs – Channel A and Channel B. Each is programmed
independently of the other. Inputs can be voltage or current (50mA max using an external
shunt), thermocouples, RTDs or TTL compatible pulse inputs. Isolation is provided
between inputs and the rest of the system. The channels are not isolated from each other.
Connection detail for the various inputs is shown in Figure 2.4.
When connecting the signal wires, keep polarities correct. The screw terminals are
marked on the rear panel - there are four connections per channel. The high or positive
Figure 2.4 - Connection Detail
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