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724-746-5500 | blackbox.com
Chapter 4: E2 Controller
4.9.7 Digital Output Packed Bit Variables
Table 4-35. Digital Output Packed Bit Variables.
Bit
Digital Outputs 1
Digital Outputs 2
0
Global alarm
Reserved
1
Custom alarm 1
Reserved
2
Master fan enable
Reserved
3
DX1 enable
Reserved
4
DX1 liquid line solenoid
Reserved
5
Humidifier enable
Reserved
6
Dual power output A
Reserved
7
Dual power output B
Reserved
8
Pump enable
Reserved
9
Custom alarm 2
Reserved
10
Custom alarm 3
Reserved
11
Reserved
Reserved
12
Reserved
Reserved
13
Reserved
Reserved
14
Reserved
Reserved
15
Reserved
Reserved
The R/W BMS variables fall into two categories. Variables like the temperature setpoint are permanent. As permanent variables,
they retain their value regardless of power loss or BMS communications failure. The controller‘s flash memory is limited to one
million write cycles for permanent variables. The other category is the integer and digital variables that start with “BMS.” These
are expected to be changed frequently and require that the BMS is active when changing them. All BMS variables require that the
BMS “keep alive” parameter (Variable 100) changes between 1 and 2 within a 10-minute span. The general procedure is to set
up variables like the BMS low fan speed and then write a 1 to the BMS “keep alive” address. If the controller does not see a 2
written to the BMS “keep alive” address within 10 minutes, all the BMS variables will revert to their previous values.