14 April 1997
The two extra inputs are treated as digital inputs and their current state is viewable
in Doorway as I1 and I2. A '1' condition indicates that the terminals are shorted.
What was the OCCD state has been moved to a new 'sensor' ZDMD (S8 or C57) which
gives the Maximum zone trim as a 0-100% sensor variable.
Two new config variables will be supported
The sense of the alarm state is defined by config variable ALST 'alarm_state' 0 or 1, this
equates to open circuit or short circuit on the input terminals.
ALRM Alarm mode
This takes a number of values which function as follows
ALRM value |
Function |
0 |
no alarms |
1 |
no alarms but will respond to STOP alarms from it's own PCO modules , extra digital inputs disable boilers. Disable sense set by ALST |
2 |
Alarm active, sense determined by ALST When in alarm Boiler is Locked out, output stays on as in Cascade module |
3 |
General Alarms: Alarm state defined by ALST |
4 |
General Alarms, Alarm state defined by ALST Master off. When input 1 is in alarm all outputs are shut off, this will include Boilers on cascade modules and pumps on PCO modules |
A 'danger of freezing alarm' FREZ has also been added, this will create an alarm if the
lowest temperature reading of Flow, Return and VT is lower than 5 degC. Frost protect
should prevent this happening. Five degrees is used to allow for measurement errors and
poor conductivity between the sensor and the water.
If there is no valid Outside Air reading either from the local sensor of from the network
then this causes an alarm OUTF 'outside fail'
The state of the alarms can be monitored in Doorway by reading config variables 90-99
C90 NOAL no alarms
C91 GENA general alarm A
C92 GENB general alarm B
C93 LOKA lockout alarm A
C94 LOKB lockout alarm B
C95 FREZ danger of freezing alarm
C96 STOP Master stop alarm (firelink)
C97 OUTF outside temperature fail
To use these alarm features new Boiler hardware is required with issue 3a or later
software. The SLT also needs to have new software 1g3 or later.
Two new config variables have been added and the old config LOCK removed. The new
variables ALRM alarm_mode and ALST alarm_state mimic the operation of the same name
variables in the boiler controller.
ALRM Alarm mode
This takes a number of values which function as follows
ALRM value |
Function |
0 |
no alarms |
1 |
no alarms, digital inputs disable boilers. Disable sense set by ALST |
2 |
Alarm active, sense determined by ALST When in alarm Boiler is Locked out, output stays on. |
3 |
General Alarms: Alarm state defined by ALST |
The state of the alarms can be monitored in Doorway by reading config variables 90-99
C90 NOAL no alarms
C91 GENA general alarm A
C92 GENB general alarm B
C93 LOKA lockout alarm A
C94 LOKB lockout alarm B
The alarm features are introduced with issue 1c software, which may be run on all existing
hardware options.
Two new config variables have been added. The new variables ALRM alarm_mode and ALST
alarm_state have similar functionality to similar variables in the Boiler and Cascade
modules.
ALRM Alarm mode
This takes a number of values which function as follows
ALRM value |
Function |
0 |
no alarms |
1 |
Flow fail alarms A & B , the sense of the flow input is determined by ALST. The 'no flow' condition being equal to the alarm_state. A short is a '1' condition. |
2 |
Flow fail alarms as above, but if both pumps have been tried and still no flow has been achieved a STOP alarm is sent. |