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fix: uncaught error in read device identification #557

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merged 2 commits into from
Jun 8, 2024
Merged

fix: uncaught error in read device identification #557

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7fc8326
fix: uncaught exception
everhardt Jun 7, 2024
1343df2
fix: two interpretations of numOfObjects
everhardt Jun 7, 2024
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100 changes: 54 additions & 46 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -268,7 +268,10 @@ function _readFC43(data, modbus, next) {

let startAt = 8;
const result = {};
for (let i = 0; i < numOfObjects; i++) {
// The modbus specification states that numOfObjects is the number of
// objects in the response, but the example on page 45 shows the total
// number over all responses. Therefore be careful about reading more data than available
for (let i = 0; i < numOfObjects && startAt < data.length; i++) {
const objectId = parseInt(data.readUInt8(startAt));
const objectLength = parseInt(data.readUInt8(startAt + 1));
const startOfData = startAt + 2;
Expand Down Expand Up @@ -496,51 +499,56 @@ function _onReceive(data) {

/* parse incoming data
*/

switch (code) {
case 1:
case 2:
// Read Coil Status (FC=01)
// Read Input Status (FC=02)
_readFC2(data, next);
break;
case 3:
case 4:
// Read Input Registers (FC=04)
// Read Holding Registers (FC=03)
if (modbus._enron && !(transaction.nextDataAddress >= modbus._enronTables.shortRange[0] && transaction.nextDataAddress <= modbus._enronTables.shortRange[1])) {
_readFC3or4Enron(data, next);
} else {
_readFC3or4(data, next);
}
break;
case 5:
// Force Single Coil
_readFC5(data, next);
break;
case 6:
// Preset Single Register
if (modbus._enron && !(transaction.nextDataAddress >= modbus._enronTables.shortRange[0] && transaction.nextDataAddress <= modbus._enronTables.shortRange[1])) {
_readFC6Enron(data, next);
} else {
_readFC6(data, next);
}
break;
case 15:
case 16:
// Force Multiple Coils
// Preset Multiple Registers
_readFC16(data, next);
break;
case 17:
_readFC17(data, next);
break;
case 20:
_readFC20(data, transaction.next);
break;
case 43:
// read device identification
_readFC43(data, modbus, next);
try {
switch (code) {
case 1:
case 2:
// Read Coil Status (FC=01)
// Read Input Status (FC=02)
_readFC2(data, next);
break;
case 3:
case 4:
// Read Input Registers (FC=04)
// Read Holding Registers (FC=03)
if (modbus._enron && !(transaction.nextDataAddress >= modbus._enronTables.shortRange[0] && transaction.nextDataAddress <= modbus._enronTables.shortRange[1])) {
_readFC3or4Enron(data, next);
} else {
_readFC3or4(data, next);
}
break;
case 5:
// Force Single Coil
_readFC5(data, next);
break;
case 6:
// Preset Single Register
if (modbus._enron && !(transaction.nextDataAddress >= modbus._enronTables.shortRange[0] && transaction.nextDataAddress <= modbus._enronTables.shortRange[1])) {
_readFC6Enron(data, next);
} else {
_readFC6(data, next);
}
break;
case 15:
case 16:
// Force Multiple Coils
// Preset Multiple Registers
_readFC16(data, next);
break;
case 17:
_readFC17(data, next);
break;
case 20:
_readFC20(data, transaction.next);
break;
case 43:
// read device identification
_readFC43(data, modbus, next);
}
} catch (e) {
if (transaction.next) {
next(e);
}
}
}

Expand Down
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