Channel Switching (Pv Input 2 Channel Model) - Honeywell DCP551 Mark ΙΙ User Manual

Chapter 5. FUNCTIONS

Channel switching (PV input 2 channel model)

Switching types
NOTE
Low-temperature, high-temperature switching systems
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The following switching types are provided.
• Selecting high and low-temperature sensors for PV CH1 (CH1 below) and PV CH2
(CH2 below)
(1) CH1 is a low-temperature sensor + CH2 is a high-temperature sensor
(2) CH1 is a high-temperature sensor + CH2 is a low-temperature sensor
• CH tied for control use
PV tied for operation and control
(1) Tied CH1 PV
(2) Tied CH2 PV
• Backup switching
Two temperature sensors are used. Thus if one sensor should breakdown, the pro-
gram can switch to the other and continue normal operation. The main channel (CH1)
is used for operation and control. In the event of an overrange (up or downscale), the
subchannel (CH2) is used for operation and control to ensure normal operation.
When both the main and subchannels are in overrange, the main channel is used.
The manipulated variable setting during this overrange is valid. The normal channel
is CH1 and the subchannel is CH2. Note, however, that when 7 is set in one of setup
C71 C74
data to , this situation is reversed when an external switch is turned on.
Switching type
C25
Setup data setting
0: Low-temperature CH1, high-temperature CH2
1: Low-temperature CH2, high-temperature CH1
2: CH1 setting
3: CH2 setting
4: Backup switching
The following switching system is used when CH1 is a low-temperature sensor and CH2
is a high-temperature sensor or CH1 is a high-temperature sensor and CH2 is a low-tem-
parature sensor.
• Switching using the external switches
To switch using the external switches, set 0 in setup data
C71 C74
to .
Switch to CH1 when the external switches are off and switch to CH2 when they are
on. When the external switches are off, the CPL communications command (WS or
WB) can be used to switch between CH1 and CH2.
C26
and 7 in one of settings