Table of Contents

Venus and Loge protocol

Venus functions as a gateway between a local 485 network and a remote master which is connected via a TNC and radio.

Addresses

All devices including Venus have a system address. When a received TNC packet is not for Venus, the packet is forwarded onto the local 485 network. Responses from the 485 network are forwarded back out the TNC to the calling party.

Packet format

The packet format consists of:

Offset contents description
0 0x7F Presynch1
1 0xFE Presynch2
2 0xaa Destination address
3 0xaa Source address
4 0xnn packet data length
5 0xpp Opcode
6-n0xzzdata bytes
z1CRC LoCRC byte lo
z2CRC HiCRC byte hi

LOGE Status Packet format

Offset contents description
0 0x7F Presynch1
1 0xFE Presynch2
2 0xaa Destination address
3 0xaa Source address
4 0xnn packet data length
5 0xpp Opcode
60xzzVersion Major
70xzzVersion Minor
80xzzInside T LSD
90xzzInside T MSD
100xzzOutside T LSD
110xzzOutside T MSD
120xzzrelays
120xzzerrors
z1CRC LoCRC byte lo
z2CRC HiCRC byte hi

Opcodes

The following opcodes have been defined for the system:

Opcode Val Neumonic Meaning
0x02LG_STATUS_QUERYQuery the status of all LOGE functions: temperatures, relays, version
0x03VN_ALERTAn alert message from Venus. The data contains where the alert originates
0x04VN_QUERYQuery the status of Venus functions
0x05LG_STATUS_REPLYStatus reply from LOGE. This will be encapsulated in Venus data when forwarded.
0x06VN_STATUS_REPLYStatus reply of Venus data.
0x07LG_RQTEMP_HISTORYRequest temperature history from LOGE.
0x08VN_RQTEMP_HISTORYRequest temperature history from Venus.

Typical scenarios

1. BB Venus periodically polls LOGE, LOGE responds with status

2. Downing Venus polls LOGE. BB Venus receives poll, sends to LOGE, LOGE responds, Venus sends it out the gateway to the TNC