Service manual

A DJM3.2 MANUAL
Multiple Room Sensors
Four sensors can be wired to give an average reading of room temperatures to the TRAC control.
They must be wired in a series/parallel arrangement. The drawing above drawing shows a circuit
making use of the built in sensor in the TE6100 Johnson Sensor/Setpoint assembly and using TE6000
sensors for the other three. (The other three could also be TE6100, just using the sensor wires .)
TE
6000
TE6000
Grey
X
V
Orange
Blue
Built in TE6100
Sensor Element
TE6000
Violet
Z
Y
BMS Reset (continuous blower only)
Dipswitch one must be on to activate this option. This option requires an analogue voltage or current
signal to be wired to the optically isolated + and Β terminals. The analogue input signal proportionally
increases the calculated discharge air set-point. The calculated discharge set-point equals the dial
discharge set-point plus the input signal multiplied by a reset ratio factor.
NOTE: The direction of reset is UP ONLY. Refer to Page 16 for more information on
BMS reset.
The maximum amount of reset is adjustable from 15 to 60ºF. The very maximum discharge
temperature (dial set-point plus reset) is limited to 120ºF. See BMS CALIBRATION below.
The BMS reset option is activated by dipswitch 1. Reset ratio pot is
Pot Reset Ratio.
NOTE: As a standard, the DJM3 is designed to operate with 4-20 ma or 2-10 VDC into a
500-ohm load.
Some BMS devices do not have enough drive (va) to provide a full 10 VDC when connected to a 500-
ohm load. The input resistance for this operation can be increased to 1500 ohms by cutting resistor R43. (To
cut this resistor you must turn the board over. It is located on the back of the larger board, just below the dipswitch
block and beside Pot Reset Ratio. This is a 1-watt, 680-ohm resistor colours blue, grey, brown, gold.)
BMS reset is not truly linear. Reset will usually begin at about 4 volts. Following, is an example of
reset from one application that gives a 13ºC reset.
Page 15 Revised: 06/18/033/11/99