West Control Solutions N6600 - Manual (Page 81)

primary winding of which carries the heater current. The current carried by the
primary winding and the transformer ratio are then taken into account when
setting the Heater Current parameters (see Volume 1, Section 3).
1.3.8 Relay Outputs
The contacts are rated at 2A resistive at 120/240V AC.
1.3.9 SSR Drive Outputs
These outputs produce a time-proportioned non-isolated DC signal:
Output 1: >10V DC into 500 Ω minimum
Output 2: >4.5V DC into 250 Ω minimum
1.3.10 Solid State Outputs
These outputs provide up to 1A AC drive with a longer lifetime than an
electromechanical relay. For further details, refer to Appendix A.
1.3.11 DC Outputs
Only Output 3 may be a DC output (Recorder Output only). See Appendix A.
1.3.12 RS485 Serial Communications Link
The cable used should be suitable for data transfer at the selected rate (1200,
2400, 4800 or 9600 Baud) over the required distance. Transmitters/receivers
conform to the recommendations in the EIA Standard RS485.
The “A" terminal on the Controller should be connected to the “A” terminal on the
master device; the “B" terminal on the Controller should be connected to the “B”
terminal on the master device. Where several Controllers are connected to one
master port, the master port transceiver in the active state should be capable of
driving a load of 12k Ω per Controller; the master port transceiver in the passive
state must have pull-up/pull-down resistors of sufficiently low impedance to ensure
that it remains in the quiescent state whilst supplying up to
± 100 µ A each to the
Controller transceivers in the high impedance state.
NOTES:
1. The RS485 Serial Communications option and the Dual Setpoint/Quick
Transfer option are mutually exclusive.
2. The Controller receiver presents 1
4
standard RS485 unit load. The total
receiver load on the communications system must not exceed 32 standard
RS485 unit loads.
S075-1 1-7
PM-0075