SNAP Controller and Brain Comparison

Opto 22 SNAP PAC controllers and SNAP PAC brains serve some of the same functions in your SNAP PAC System, but they also differ.
This chart compares the features of the latest PACs and brains, with minimum firmware version R10.0 and PAC Project R10.0.
Note that due to unavailable essential parts, SNAP PAC brains are obsolete as of 2022. Use an R-1 PAC instead.
For more details, see the SNAP PAC Controller & Brain Comparison Chart (form 1677).

  Software Standalone PACs Rack-mounted PACs Ethernet Brains (OBSOLETE) Serial Brains
(OBSOLETE)
Feature SoftPAC SNAP-PAC-S1 SNAP-PAC-S2 SNAP-PAC-R1

SNAP-PAC-R2 
(Obsolete)

SNAP-PAC-EB1 SNAP-PAC-EB2 SNAP-PAC-SB1 SNAP-PAC-SB2
Runs PAC Control strategies • • • • •        
Maximum PAC Control charts running at once (plus host task) 64 32 32 16 16        
   Communication
Two independent Ethernet network interfaces (two IP addresses) a • • • •        
Two switched Ethernet network interfaces (one IP address) for multi-drop configuration           • •    
Total number of RS-232 serial ports b 2 4c 1 1 0 0 0 0
Total number of RS-485 serial ports b 1 4c 0 0 0 0 1 1
Maximum Ethernet host connections to port 22001 (control side)w 31 31 31 31 31        
Maximum host connections to port 2001 (I/O side) 15 15 15 15 15 15 15 15 15
   Protocols
TCP/IP, UDP/IP • • • • • • •    
EtherNet/IP (Allen-Bradley RSLogix systems, others)   • • • • • •    
Modbus/TCP (slave)d   • • • • • •    
OPC driver support • • • • • • • •f •f
RESTful API   • • • •        
HTTP/HTTPS   • • • •        
OptoMMP memory-mapped protocol •g • • • • • • • •
SNMP (network management)   • • • • • •    
FTP server, file system   • • • • • •    
FTP client • • • • •        
SMTP (email client with authentication and attachments • • • • •        
  General  
SNAP-PAC nodes for Node-RED; RESTful API   • • • •        
Direct access to hard drive, network drives (Dropbox, etc.) •                
Realtime clock a • • • • • • • •
Backup battery (recharges when brain has power)h   • • • • • • • •
Physical RAM (MB)
RAM available for PAC Control strategy (MB)
Battery-backed RAM (MB)
Flash memory (MB)
a
64
8
i
32
16
8
16
32
16
8
16
16
4
2
​8
16
4
2
​8
16
--
--
8
16
--
--
8
16
--
--
8
16
--
--
8
Removable data storage (microSD card slot) a 32 GB maxk 32 GB maxk 32 GB maxk 32 GB maxk        
32-bit processor a • • • • • • • •
Floating-point unit (FPU) a • • • •        
Power requirements a 8-32 VDCl
10W-11.3 W max
5.0 to 5.2 VDC
@ 1.2 to 1.5 A
5.0 to 5.2 VDC
@ 750 mA-1.0 A
5.0 to 5.2 VDC
​@ 750 mA-1.0 A
Operating temperature (degrees C)
Storage temperature (degrees C)
a -20 to 60
-40 to 85
-20 to 60
​-40 to 85
-20 to 60
​-40 to 85
-20 to 60
​-40 to 85
Humidity (non-condensing) a 0-95% 0-95% 0-95% 0-95%
Compatible with SNAP PAC EB (Ethernet) brains • • • • •        
Compatible with SNAP PAC SB (serial) brains   • •            
Compatible with SNAP PAC R-series controllers • • • • •        
Compatible with groov EPIC  • • • • •        
Compatible with groov RIO  • • • • •        
Combination controller and I/O processorm       • •        
Mounts on SNAP PAC I/O mounting rack        • • • • • •
Mounts on SNAP B-series I/O mounting rack       •v          
Maximum number of modules allowed on largest rack: Any mix of 16 digital, 16 analog, and 8 serial       •o •o • • • •
   Digital I/O point features
Input latching       • • • • • •
On/off status       • • • • • •
Watchdog timer       • • • • • •
High-speed counting (up to 20 kHz)q       •   •   •  
Quadrature countingr       •   •   •  
On-pulse and off-pulse measurementq       •   •   •  
Frequency and Period measurementq       •   •   •  
TPO (time-proportional output)       • • • • • •
Digital totalizingq       • • • • • •
Pulse generation (continuous square wave, N pulses, on-pulse, off-pulse)       • • • • • •
   Analog I/O point features
Thermocouple linearization (32-bit floating point for linearized values)       • • • • • •
Minimum/maximum values       • • • • • •
Offset and gain       • • • • • •
Scaling       • • • • • •
TPO (time-proportional output)s       • • • • • •
Output clamping       • • • • • •
Filter weight       • • • • • •
Watchdog timer       • • • • • •
Analog totalizingt       • • • • • •
Rampingt       • • • • • •
PID logic (maximum 96 PID loops per controller or brain)       • • • • • •
Data logging       • • • • • •
Digital events,alarm events, serial events       • • • • •u •u
Events messaging       • • • •    
UDP streaming of I/O data to host       • • • •    
I/O point data mirroring and memory map copying       • • • •    
a As provided by the Microsoft Windows-based computer SoftPAC runs on.
b SoftPAC cannot communicate through serial ports on the PC.
c Serial ports are software configurable for RS-232 or RS-485.
d PAC firmware >=R9.4b, 8 max connections. Lower firmware, 2 max connections.
f Available with OptoOPCServer and PAC Control, through a SNAP PAC controller.
g SoftPAC includes Status Read, Status Write, and Scratch Pad memory map areas.
hModels manufactured before August 2007 and S1s with serial numbers 625653 and lower have user-replacable backup batteries. See original user's guide.
i Flash memory function implemented via a file; size is limited only by disc space
k PAC firmware 9.4a and loader 6.1a or higher. S-series with microSD & manufacture date older than 06/2014 supports maximum 2 GB microSD.
l Units with serial numbers lower than 500,000 have an 8-24VDC input voltage rating. Verify voltage on the unit's faceplate before applying power.
n For compatibility with legacy Opto 22 hardware, see the Legacy and Current SNAP Product Comparison and Compatibility Charts (form 1693).
m I/O features vary by model. For details, see the SNAP PAC Controller and Brain Comparison Chart (form 1677).
o SNAP-PAC-R1s with serial numbers lower than 600,000 and all SNAP-PAC-R1-Bs; limited to 4-point digital modules per rack.
p Not supported: serial, motion control, Profibus, & Wiegand modules.
q Four-channel modules only; not high-density modules.
r Requires a SNAP-IDC5Q quadrature input module.
s Requires a SNAP analog TPO module (SNAP-AOD-29 or SNAP-AOD-29-HFi).
t Requires a SNAP PAC controller and PAC Control commands.
u Does not support serial events.
v Only applies to SNAP-PAC-R1-B (Obsolete).
w Host performance may deteriorate near maximum.